<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <button onclick="send()">ajax请求:/hello</button>
    <!-- 可以类似的完成PostServlet的ajax请求 -->
</body>
    <script src="hello.js">
    </script>
</html>